Lady GaGa feels ''miserable'' every day after suffering a sexual assault at 19.

The 'Pokerface' hitmaker was raped when she was just 19-years-old and admits it still affects her to this day, and at times she can have a ''hard time breathing'' and her ''whole body goes into a spasm''.

She said: ''No one else knew. It was almost like I tried to erase it from my brain. And when it finally came out, it was like a big, ugly monster. And you have to face the monster to heal. For me, with my mental health issues, half of the battle in the beginning was, I felt like I was lying to the world because I was feeling so much pain but nobody knew. So that's why I came out and said that I have PTSD, because I don't want to hide - any more than I already have to.

''I feel stunned. Or stunted. You know that feeling when you're on a roller coaster and you're just about to go down the really steep slope? That fear and the drop in your stomach? My diaphragm seizes up. Then I have a hard time breathing, and my whole body goes into a spasm. And I begin to cry. That's what it feels like for trauma victims every day, and it's ... miserable. I always say that trauma has a brain. And it works its way into everything that you do.''

Meanwhile, the 32-year-old singer also revealed she gets ''so irritated'' when people say her fibromyalgia isn't real.

She told the October issue of Vogue magazine: ''I get so irritated with people who don't believe fibromyalgia is real. For me, and I think for many others, it's really a cyclone of anxiety, depression, PTSD, trauma, and panic disorder, all of which sends the nervous system into overdrive, and then you have nerve pain as a result. People need to be more compassionate. Chronic pain is no joke. And it's every day waking up not knowing how you're going to feel.''